The present invention relates generally to the field of information processing by digital computers and, more particularly, to the processing and presentation of information in graphic form by application programs, particularly electronic spreadsheets.
Before computers, numerical analyses, particularly financial ones, were usually prepared on an accountant's columnar pad or spreadsheet, with pencil and calculator in hand. By organizing data into columns and rows, spreadsheets afford the rapid assimilation of information by a reader. The task of preparing a spreadsheet on paper, however, is not quite so fast. Instead, the process tends to be very slow, as each entry must be tediously calculated and entered into the spreadsheet. Since all calculations are the responsibility of the preparer, manually prepared spreadsheets are also prone to errors. Hence, preparation of spreadsheets by hand is slow, tedious, and unreliable.
With the advent of microcomputers, a solution was forthcoming in the form of "electronic spreadsheets." Better known simply as "spreadsheets," these software programs provide a computerized replacement for the traditional financial modeling tools: the accountant's columnar pad, pencil, and calculator. In some regards, spreadsheet programs are to those tools what wordprocessors are to typewriters. Spreadsheets offer dramatic improvements in ease of creating, editing, and using financial models.
A typical spreadsheet program configures the memory of a computer to resemble the column/row or grid format of an accountant's columnar pad, thus providing a visual calculator for a user. Because this "pad" exists dynamically in the computer's memory, however, it differs from paper pads in several important ways. Locations in the electronic spreadsheet, for example, must be communicated to the computer in a format which it can understand. A common scheme for accomplishing this is to assign a number to each row in a spreadsheet, and a letter to each column. To reference a location at column A and row 1 (i.e., the upper-left hand corner), for example, the user types in "A1". In this manner, the spreadsheet defines an addressable storage location or "cell" at each intersection of a row with a column.
Data entry into an electronic spreadsheet occurs in much the same manner that information would be entered on an accountant's pad. After a screen cursor is positioned at a desired location, the user can enter alphanumeric information. Besides holding text and numeric information, however, spreadsheet cells can store special instructions or "formulas" specifying calculations to be performed on the numbers stored in spreadsheet cells. In this fashion, cell references can serve as variables in an equation, thereby allowing precise mathematical relationships to be defined between cells. The structure and operation of a spreadsheet program, including advanced functions such as "@functions" and macros, are documented in the technical, trade, and patent literature. For an overview, see e.g., Cobb, D., Using 1-2-3, Que corp., 1985; and Campbell, M., Quattro Pro 4.0 Handbook, 4th Ed., 1992. The disclosures of each of the foregoing references are hereby incorporated by reference.
Electronic spreadsheets offer many advantages over their paper counterparts. For one, electronic spreadsheets are much larger (i.e., hold more information) than their paper counterparts; electronic spreadsheets having thousands or even millions of cells are not uncommon. Spreadsheet programs also allow users to perform "what if" scenarios. After a set of mathematical relationships has been entered into a worksheet, the spread of information can be recalculated using different sets of assumptions, with the results of each recalculation appearing almost instantaneously. Performing this operation manually, with paper and pencil, would require recalculating every relationship in the model with each change made.
A particular feature of electronic spreadsheets is the ability to view data in graphic form--to visually inspect important trends and characteristics of one's data. Consider, for instance, a user who has created a spreadsheet storing a year's worth of sales figures for various product lines. Suppose the user desires the sales data to be presented graphically, so that the user can, say, easily determine the peak sales months for each product. Conventional spreadsheet systems include a multitude of graph types for this very purpose. The user would proceed to select the data cells of interest and then pick a desired graph type for his or her data.
A problem exists, however. The user has no formal training in graph theory and is, in fact, quite bewildered by the vast selection of graph types. And to make matters worse, the user has not had an opportunity to master the user commands necessary for choosing among the various graph types because, like most other users, the user has not had time to read the user manual. With conventional electronic spreadsheets, therefore, the user must not only understand which graph type is appropriate for his or her data, but the user must also master the user commands necessary for selecting a particular type from among the numerous types available. Finding conventional approaches daunting, therefore, most users simply accept whatever default graph type is provided by his or her system. Unfortunately for the user, the default graph type provided by the system is no more suited from revealing important trends and characteristics of the user's data than if the user had simply selected a graph type at random.